首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3014篇
  免费   141篇
  国内免费   9篇
耳鼻咽喉   19篇
儿科学   98篇
妇产科学   92篇
基础医学   497篇
口腔科学   76篇
临床医学   223篇
内科学   729篇
皮肤病学   72篇
神经病学   159篇
特种医学   32篇
外科学   255篇
综合类   26篇
一般理论   1篇
预防医学   404篇
眼科学   53篇
药学   258篇
中国医学   15篇
肿瘤学   155篇
  2023年   24篇
  2022年   51篇
  2021年   94篇
  2020年   47篇
  2019年   73篇
  2018年   77篇
  2017年   71篇
  2016年   62篇
  2015年   73篇
  2014年   124篇
  2013年   170篇
  2012年   269篇
  2011年   242篇
  2010年   142篇
  2009年   114篇
  2008年   201篇
  2007年   226篇
  2006年   185篇
  2005年   177篇
  2004年   163篇
  2003年   171篇
  2002年   164篇
  2001年   28篇
  2000年   18篇
  1999年   21篇
  1998年   27篇
  1997年   20篇
  1996年   18篇
  1995年   13篇
  1994年   11篇
  1993年   12篇
  1992年   4篇
  1991年   5篇
  1990年   10篇
  1989年   6篇
  1988年   5篇
  1987年   6篇
  1986年   3篇
  1985年   3篇
  1983年   4篇
  1982年   7篇
  1981年   3篇
  1978年   3篇
  1975年   3篇
  1972年   1篇
  1971年   2篇
  1969年   1篇
  1968年   2篇
  1967年   2篇
  1926年   1篇
排序方式: 共有3164条查询结果,搜索用时 593 毫秒
21.
Tuberculosis is a public health problem. If the current trends continue, is expected to arrive to 10.2 million of new cases in 2005. There are three studies accomplished in 1995 in Mexican patients. The results show important difficulty in the application and the follow-up of the program of control of the tuberculosis, what has caused accumulation of chronic cases, moderate rate of primary resistance and alarming levels of primary and secondary multiresistance (23%). Mechanism of protective immunity against mycobacterium tuberculosis (MTB) in humans have not been clarified. Different subpopulations of lymphocytes CD4, CD8 and other populations as well as macrophages, and monocytes, have an important role. In industrialized countries, the managing of the MDRTB is based on the use of individualized treatments with second line drugs according to susceptibility test, however the foregoing has not been possible to apply it middle or low income countries. WHO has launches the initiative "DOTS plus" that consist in the administration of a standarized regimen on the basis of epidemiology of resistance in the country or region.  相似文献   
22.
We report a 89-year-old female diagnosed with chronic myelomonocytic leukemia (CMMoL) presenting with a monosomy 15. To our knowledge, this is the second reported case of CMMoL with monosomy 15. On the other hand, monosomy 15 in complex karyotypes is a frequent chromosome aberration in myelodysplastic syndromes, particularly in refractory anemia with excess of blasts.  相似文献   
23.
The effects of the chronic inhibition of nitric oxide (NO) on renal hemodynamics and tubular function were studied in rats treated for 8 weeks with the NO synthesis inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME; 40 mg/kg/day). In addition, the effect of L-NAME administration on vasoactive systems (renin-angiotensin system, aldosterone, catecholamines, endothelin, and thromboxane A(2)) was evaluated. Chronic inhibition of NO significantly elevated blood pressure, reduced glomerular filtration rate and renal blood flow, blunted the pressure-diuresis-natriuresis response, and increased protein urine excretion. All these changes were associated with blunted nitrite production in response to acetylcholine in glomeruli. No changes were observed in the plasma levels of either renin activity, aldosterone, or endothelin in L-NAME-treated rats. Similarly, no differences were observed in the urinary excretion of thromboxane B(2) between both group of animals. By contrast, plasma concentrations of both epinephrine and norepinephrine were elevated in rats treated with L-NAME. In summary, the results show that chronic blockade of NO produced not only alterations in renal function, but also renal damage, suggesting an important renoprotective role of NO. An activation of sympathoadrenal system could participate in these renal alterations.  相似文献   
24.
25.
26.
The net impact of cytomegalovirus (CMV) DNAemia on overall mortality (OM) and nonrelapse mortality (NRM) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a matter of debate. This was a retrospective, multicenter, noninterventional study finally including 749 patients. CMV DNA monitoring was conducted by real-time polymerase chain reaction (PCR) assays. Clinical outcomes of interest were OM and NRM through day 365 after allo-HSCT. The cumulative incidence of CMV DNAemia in this cohort was 52.6%. A total of 306 out of 382 patients with CMV DNAemia received preemptive antiviral therapy (PET). PET use for CMV DNAemia, but not the occurrence of CMV DNAemia, taken as a qualitative variable, was associated with increased OM and NRM in univariate but not in adjusted models. A subcohort analysis including patients monitored by the COBAS Ampliprep/COBAS Taqman CMV Test showed that OM and NRM were comparable in patients in whom either low or high plasma CMV DNA threshold (<500 vs ≥500 IU/mL) was used for PET initiation. In conclusion, CMV DNAemia was not associated with increased OM and NRM in allo-HSCT recipients. The potential impact of PET use on mortality was not proven but merits further research.  相似文献   
27.
28.
Mantle cell lymphoma (MCL) is a B-cell neoplasm with a relatively aggressive clinical course. There is a very small subgroup of patients who present with atypical lymphocytes in peripheral blood, with or without lymphocytosis, lymphadenopathy, or splenomegaly, and with an indolent clinical course. They frequently show mutated IgV(H) genes and CD5 negativity. We report an asymptomatic elderly patient who presented with a single submandibular lymphadenopathy. The biopsy showed immunophenotype and t(11;14)(q13;q32) consistent with MCL. The abnormal lymphoid population was also detected in peripheral blood and bone marrow. The patient has remained asymptomatic for 5 years without receiving any therapy. It is uncertain whether these cases represent an early-stage event in the development or an indolent form of MCL. The existence of such asymptomatic patients with an indolent clinical course should induce a strict clinical judgment in terms of therapeutic decisions.  相似文献   
29.
Immunohistochemical localization of leptin in rat kidney   总被引:5,自引:0,他引:5  
  相似文献   
30.
Mercury and selenium interaction: A review   总被引:10,自引:1,他引:9  
This paper reviews studies on mercury and selenium interaction. It includes the effects of selenium on mercury toxicity on the organism, organ/tissue, and subcellular levels. The paper also touches on possible mechanisms for the "protective action" of selenium against mercury toxicity and deals briefly with the synergism between the two elements.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号